Field of Invention
The present invention relates to a magnetic field probe. More particularly, the present invention relates to a difference magnetic field probe.
Description of Related Art
Recently, the sizes of electronic products have become smaller and smaller, and performance requirements for radio transmission and high speed circuits have become higher and higher. As a result, the circuits required are more and more complex so that the difficulty in circuit integration has been increasing. One of the reasons is that the radio frequency devices disposed in the circuits cause signal integrity (SI) problem, electromagnetic interference (EMI) problem, etc. Such problems increase the difficulties in circuit design and debugging. During a debugging process, a magnetic field probe is usually utilized to scan and detect a magnetic field distribution nearby an electronic product so as to rapidly detect an electromagnetic interference source.
Due to the small sizes of the devices under test and the increased sources of interference, market demand for magnetic field probes having a high spatial resolution and a wide operating bandwidth (related to electric field isolation and resonance frequency) has been increasing. However, the smaller the distance between a magnetic field probe and a device under test is, the more obvious the interference caused by electric field noises is. Accordingly, the result of magnetic field detection is impacted. A traditional magnetic field probe usually improves the spatial resolution by shrinking the loop size, but the reduced loop size means lower magnetic loop probe sensitivity. Although increasing the loop size can reduce the interference caused by electric field noises, the spatial resolution is reduced, too. Moreover, the resonance frequency tends to occur at low detection frequencies. As a result, the probe fails to detect the correct magnetic field distribution at the resonance frequency.